<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>勉强的计算器</title>
<script type="text/javascript" src="jisuangqi2.js">

</script>
</head>

<body>
<form action=" " name="form1">
<input type="text" name="firstNumber" onchange="checkNumber(this)" />
<select name="operator">
<option value="0">+</option>
<option value="1">-</option>
<option value="2">*</option>
<option value="3">/</option>
</select>
<input type="text" name="secondNumber" onchange="checkNumber(this)" />
<input type="button" value="=" onclick="calculate()" />
<input type="text" name="result" readonly="readonly" />
</form>

<div>
	本来想做键盘的那种，可是点击上面显示数字不会改变，就放弃了。。。
</div>
</body>
</html>